Cadmium sulfide (CdS) nanoparticles dotted on the surface of multiwalled carbon nanotubes (MWCNTs) have been synthesized by the polyol method. The as-prepared materials were characterized by x-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Brunauer-Emmett-Teller adsorption analysis. The results indicate that CdS nanoparticles with diameter of 5-8 nm are thickly and uniformly coated on the surface of the MWCNTs. The photodegradation of azo dye using these materials was evaluated by the degradation of Brilliant Red X-3B under visible light. The coated nanotubes show higher photocatalytic activity than both CdS alone and a CdS/activated carbon sample; in addition, there is an optimum content of MWCNTs. The presence of MWCNTs can also hamper the photocorrosion of CdS. The mechanism for the enhancement of MWCNTs on the adsorption and photocatalytic property of CdS is investigated for the first time.

Using X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), we have studied the growth of the single crystalline nanowires of Ag, Cu, Ni and Co metals in the small pores (50 nm). We find that the preferential growth surface of the single crystalline nanowires is on the atomically rough surfaces such as fcc(110) and hcp(10\mathop1\limits_0). We have proposed a new model to explain the growth of the nanowires of fcc and hcp metals. In this model we argue that the preferential growth should depend on the number of sites for dehydration of hydrated metal ions on a metal surface. The dehydration occurs only at the apex site of a protruding surface atom since the apex site of the protruding surface atom has an enhanced electrical field. The sites for the dehydration on the fcc(110) and hcp(10\mathop1\limits_0) atomically rough planes are in number much larger than those on the fcc(111) and hcp(0001) atomically smooth surfaces, thus leading to the preferential growth on the fcc(110) and hcp(10\mathop1\limits_0) planes.

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Anisotropic Bi2Te3‐based thermoelectric materials have drawn extensive interest in the past decades. Here, n‐type Bi2Te2.7Se0.3 films with superhigh figure of merit are developed through anisotropy control via tuning an external electric field and deposition anisotropy. It is found that the angle of interplanar grain boundaries between (0 1 5) and (0 1 11) planes can be tuned by the applied external electric field, which leads to the strengthened anisotropy of electron mobility and simultaneously maintains low lattice thermal conductivity. Dominated by the unique change in the anisotropy of both lattice thermal conductivity and electron mobility, a record‐high zT value of ≈1.6 at room temperature can be achieved in the as‐deposited n‐type Bi2Te2.7Se0.3 film under 20 V external electric field. This work indicates that the electric field–induced deposition anisotropy control can be used to develop high‐performance Bi2Te3‐based thermoelectric films.

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